Mitsuharu Kodaka

Electron microscopic evaluations of clot morphology during thrombelastography

In this study, we characterized clot morphology with a scanning electron microscope (SEM) at time points corresponding to the commonly used thrombelastography (TEG®) variables, illustrating the correlation of the physical clot formation with TEG® tracings. The first channel of the TEG® analyzer was used to obtain the tracings of clot formation, while the sub-samples for the SEM were obtained from the second TEG® channel. Different types of samples were examined, including whole blood, abciximab-treated whole blood, platelet-rich plasma (PRP), and abciximab-treated PRP. The SEM images were obtained at reaction time, different amplitudes (5–30 mm), maximum amplitude (MA), and at amplitude 60 min after MA. In the whole blood, coarse fibrin and activated platelets were observed at reaction time and fibrin strands progressively became more solid and intertwined at amplitude 10 mm and thereafter. Red blood cells were surrounded with fibrin strands at amplitude 30 mm and were tightly packed by fibrin strands at MA. In abciximab-treated whole blood, red blood cell shape was maintained at MA. The process of fibrin formation and platelet activation was also examined in PRP. Abciximab did not block platelet shape change, although the blockage of fibrin binding to platelets was shown on the TEG® analyzer. In summary, we have shown structural changes of the forming clot in relation to TEG® variables.

The influence of gender on loss of consciousness with sevoflurane or propofol.

Studies have suggested that hypnotic requirements for general anesthesia and emergence may be influenced by gender. In this study, we examined the effect of gender on the hypnotic requirement for loss of consciousness (LOC) using either a volatile (sevoflurane) or an IV (propofol) anesthetic. One-hundred-fifteen unpremedicated, ASA physical status I–II patients, aged 18–40 yr old, received either sevoflurane by mask to a predetermined end-tidal concentration (%ETsevo) or propofol by target-controlled infusion (effect site) while breathing spontaneously. After sufficient time for equilibration, LOC was assessed by lack of response to mild prodding. The up-down method of Dixon was used to determine the hypnotic target concentration at 50% response (LOC50). No statistically significant difference in LOC50 was noted between men and women for sevoflurane (0.83% ± 0.1% and 0.92% ± 0.09% ET, respectively). Men required significantly more propofol than women (2.9 ± 0.2 versus 2.7 ± 0.1 &mgr;g/mL, respectively). However, there was no difference in the bispectral index (BIS) at LOC for men or women with either hypnotic anesthetic. This investigation identified a small, statistically significant difference in hypnotic requirement at LOC50 between men and women with propofol but not with sevoflurane. As defined by BIS, men and women had equivalent hypnotic states at LOC50, indicating that gender had no clinically significant effect on hypnotic requirements. However, BIS at a defined clinical end-point (LOC50) was significantly different between the sevoflurane and propofol groups, suggesting that neurophysiological effects of these anesthetics may be different.

A Method for Studying Interaction Between Non-Deporalizing Neuromuscular Blockers and Other Drugs in Vivo

In view of clinical set, there are not so many methods for studying interactions between non-deporalizing neuromuscular blockers and other drugs. We schemed out a new methods for studying the interactions mentioned above.